CARIOCA project – coral reef acclimatization to ocean acidification (video; in French and in English)

In the framework of the project CARIOCA (Coral reef acclimatization to ocean acidification at CO2 seeps) funded by the French National Agency ANR, Riccardo Rodolfo-Metalpa and the team IRD Entropie investigated a new promising CO2 vents system located in Papua New Guinea.

This site was explored by a team of geologists 20 years ago (Pichler et al 1996) who found huge volcanic emissions in a rich coral reef area. The gas discharge is composed of more than 95 % CO2 with minor CH4, N2 and O2 (Pichler et al., 1999), but most importantly H2S is completely absent and thus there is no detrimental effect from the gas phase other than a decrease of seawater pH. In addition, vents emit CO2 and fluids at high temperature, offering the timely opportunity to study coral reef responses to the combined effect of ocean acidification and warming in a natural setting.

Preliminary measurements performed by the team of Thomas Pichler confirmed the absence of any toxin elements at the study site, especially for Arsenic (As) which is almost completely removed from the hydrothermal fluid and not present in seawater near the corals.

This make CO2 vents of Ambitle Island another promising natural laboratory to study the effect of ocean acidification on coral reefs and potentially its combination with warming.

During the last fieldwork, the team performed a short documentary to explain the project goals and main results (French and English version).